Use (( )) instead of [[ ]]?

[dimitry-ishenko]

(1) I see bash-utility heavily using

[[ $# -lt 2 ]] && ...

Wouldn't it be more readable to do

(( $# < 2 )) && ...

instead? (( is used for arithmetic evaluation, which is what -lt is trying to force inside [[.

(2) Also, seeing this:

[[ $# = 0 ]] && ...

rubs me the wrong way on multiple levels.

First, we are all taught that = is assignment and == is equivalence comparison. Yes, in bash they are the same when used inside [[, but = is used for assignment elsewhere in bash and IMHO this is just a bad coding practice.

Second, operator = within [[ is used for pattern matching and not arithmetic comparison. So, it should minimally be:

[[ $# -eq 0 ]] && ...

or better yet:

(( $# == 0 )) && ...

to be more readable and consistent with (1).

[dimitry-ishenko]

I've realized I should probably take it up with bash-utility.

I don't see any activity in their repo for the past 2 years, but I've opened the same issue with them: labbots/bash-utility#1

[sgjava]

@dimitry-ishenko, knock yourself out if you can find a better bash library. I just didn't want to duplicate a lot of the boilerplate type stuff. I'm not sure how much bash really changes, thus maybe not a lot commits needed. On the plus side you can make all the Armbian stuff clean. I tried to go down the path of functional/procedural programming and not create God scripts or functions.

[dimitry-ishenko]

@sgjava I am not saying the library is bad. I actually like it. But there quite a few things that can be improved. Ideally they would be done upstream, but if they don't respond, I am willing to fork it and do the clean-ups.

[sgjava]

@dimitry-ishenko Yeah, exactly, that's why I embedded it into the project. I hate submodules since the project can change (or be deleted) and wreck your project. If you do go the submodule path just maybe create the fork under the Armbian project? I did research bash libraries out there and there aren't many. Anyways, it's all good. I'm mainly a Java, C, C++ and Python dev. I do script a lot with bash, but writing a complete project (or API) in it is more complicated than most folks think. Just missing real data types, etc. makes thing rough in my eyes.

[dimitry-ishenko]

If you do go the submodule path just maybe create the fork under the Armbian project?

IMHO this is the best approach. I don't have access to Armbian, so for now I've made my own fork here:

https://github.com/dimitry-ishenko/bash-utility

If someone could fork the upstream project in Armbian and give me write access, I can work from there. Then it can be added here as a submodule.

FWIW, I've done some clean-ups in the Array module: https://github.com/dimitry-ishenko/bash-utility/blob/master/src/array.sh and submitted PR to upstream. Will see if they respond.

[igorpecovnik]

If someone could fork the upstream project in Armbian and give me write access, I can work from there.

Invitation sent.

[sgjava]

@dimitry-ishenko sure as long as you control the submodule. If you rely on a submodule you don't own and it's deleted then you are screwed. @igorpecovnik hooked you up with access.

[Tearran]

Suggest close no fix. Unwarranted use for readability:

In Bash, (( .. )) is an arithmetic construct, while [[ .. ]] is a conditional expression. They serve different purposes and are used in different scenarios.

(( .. )) is used for arithmetic operations and comparisons. For example, you can use it to increment a variable ((i++)), or to compare two numbers ((a > b)).

On the other hand, [[ .. ]] is used for testing conditions. It is an improvement over the [ .. ] command and has several enhancements that make it a better choice if you write scripts that target Bash.

For example, it handles empty strings and strings with whitespace more intuitively, it lets you use && and || operators for boolean tests and < and > for string comparisons, it has a =~ operator for doing regular expression matches, and it lets you do pattern matching
referance;1 referance;2.

So in summary, (( .. )) is used for arithmetic operations while [[ .. ]] is used for testing conditions.

[dimitry-ishenko]

So in summary, (( .. )) is used for arithmetic operations...

You are contradicting yourself:

(( .. )) is used for arithmetic operations and comparisons. For example, you can use it to increment a variable ((i++)), or to compare two numbers ((a > b)).

Unless you include comparison operations into arithmetic operations (which they actually are, but you are seemingly trying to differentiate them).

And, what I was pointing out was that bash-utility incorrectly uses [[ ]] to compare if the number of parameters passed to a function is less than 2 or equal to 0.

[dimitry-ishenko]

BTW I do have a mostly cleaned up version of bash-util here: https://github.com/armbian/bash-util, which was supposed to become the submodule of this repo.

Unfortunately, I have not been able to complete it (due to lack of motivation). I am not sure at this point if it should be abandoned or it could still be added as a submodule and someone could finish cleaning it up concurrently.

[Tearran]

The argument was for readability. to be more readable and consistent with (1). And for readability, if this is what works for you and you would like to continue with development, I will agree with the fix. Otherwise, my convoluted point remains. It’s not something that needs fixing, it’s a preference.

[Tearran]

Second, post.
Not Shure about submodules and upstream stuff, but the lack of motivation I get.